The Peloponnesian War

Podcast Transcript

In the 5th century BC, the Greek world found itself in the middle of one of its greatest wars. This wasn’t one of their existential conflicts against the Persians; this was a war of Greeks against Greeks.

An alliance of city-states led by Athens fought a coalition led by Sparta for control of the Greek world.

Over nearly 30 years, the two city-states fought for supremacy, leaving a lasting impact on the Greek world that would change its course forever..

Learn more about the Peloponnesian War, its causes, and its resolution on this episode of Everything Everywhere Daily.

To understand the causes of the Peloponnesian War, it is essential to understand the political landscape of the Greek World in the late 5th century BC.

The Peloponnesian War was rooted in the shifting power dynamics of the Greek world following the Persian Wars, which took place from 490 to 479 BC. This was the conflict that saw many of the famous battles of antiquity, including the Battle of Marathon and Thermopylae.

During the Persian invasions, the two dominant Greek powers, Athens and Sparta, had cooperated to defeat a common enemy. However, the aftermath of that victory sowed the seeds of conflict between them.

Athens emerged from the Persian Wars not only as a symbol of Greek resistance but as a rising imperial power. It led to the formation of the Delian League in 478 BC, an alliance of city-states meant to defend against further Persian aggression.

Over time, Athens transformed this alliance into a de facto empire, compelling tribute payments, suppressing revolts, and using the league’s resources to fund its own projects, including the rebuilding of the Acropolis. The Athenians also moved the league’s treasury from Delos to Athens in 454 BC, in a show of dominance.

Sparta, traditionally the most powerful land-based state in Greece and leader of the rival Peloponnesian League, viewed Athenian expansion with increasing alarm.

If you are not familiar with the geography of Greece, the Peloponnese is a peninsula that is almost an island. It is connected to the rest of the Greek mainland by the very narrow Isthmus of Corinth, which is only 6.3 kilometers or 3.9 miles wide.

The Spartans were culturally conservative and preferred a stable balance of power. As Athens grew in economic strength, naval supremacy, and political influence, often at the expense of smaller city-states, Sparta and its allies came to see it as a direct threat to their autonomy and regional order.

The fundamental tension arose from what historians call the “Thucydides Trap,” named after the Athenian historian Thucydides, who documented much of the war.

The Thucydides Trap refers to the inevitable conflict that arises when a rising power, in this case, Athens, threatens to displace an established power, such as Sparta.

The war began in 431 BC with a strategy that seemed logical to both sides but proved deeply flawed.

The Spartan king Archidamus led annual invasions of Attica, the territory around Athens, hoping to force the Athenians into a decisive land battle where Spartan superiority would prove decisive.

The Athenians, following the strategy of their leader Pericles, withdrew their population behind their Long Walls, the defensive fortifications that connected Athens to its port at Piraeus and used their naval supremacy to raid the Peloponnesian coast.

This created a strategic stalemate that neither side had anticipated. The Spartans could devastate Athenian farmland, but they couldn’t force a decisive engagement.

The Athenians could strike coastal targets, but they couldn’t break Spartan power on land. It was like watching a heavyweight boxer fight a judo master; each was supreme in their element, but neither could force the other to fight on their preferred terms.

The turning point came with the plague that struck Athens in 430 BC. This devastating epidemic, which killed perhaps one-third of the population, including Pericles himself, fundamentally altered Athenian society and strategy.

The cramped conditions behind the Long Walls, with rural refugees packed into the city, created perfect conditions for the disease to spread. The psychological impact was even more profound, and many Athenians began to question whether the gods favored their cause.

This phase of the war, known as the Archidamian War, after the Spartan king, dragged on for a decade. The period was punctuated by battles like those at Pylos and Sphacteria, which saw the rare capture of Spartan hoplites by Athenian forces.

The war eventually paused with the Peace of Nicias, signed in 421 BC.

It was intended to be a 50-year truce between Athens and Sparta after the first phase of the Peloponnesian War. However, during what was nominally still the period of peace, the treaty had effectively collapsed.

The Battle of Mantinea fought in 418 BC, was the largest land battle of the Peloponnesian War and marked a temporary resurgence of Spartan prestige after years of military and diplomatic setbacks.

It took place during the Peace of Nicias, which showed how little regard they had for the treaty.

The battle was sparked by a shifting web of alliances: Argos, Mantinea, Elis, and Athens had formed a coalition against Sparta, threatening its dominance in the Peloponnese. In response, the Spartans, led by King Agis II, mobilized a large force to confront the alliance near the city of Mantinea in Arcadia.

The battle was a traditional hoplite clash, and despite early confusion in Spartan ranks, they achieved a clear and decisive victory, routing the coalition forces. The triumph at Mantinea restored Spartan confidence and reaffirmed their military reputation, discouraging further revolts among their allies and temporarily stabilizing the internal Greek balance of power in Sparta’s favor.

In 415 BC, Athens embarked on what would prove to be its most disastrous decision: the invasion of Sicily. This massive expedition, involving over 100 ships and thousands of men, represented both the magnificent and tragic aspects of Athenian democracy.

The plan emerged from the intersection of ambition, opportunity, and democratic politics. The wealthy young aristocrat Alcibiades envisioned a Sicilian conquest that would make Athens the master of the western Mediterranean.

It was initiated ostensibly to assist the small Sicilian city of Segesta, an ally of Athens, in its local conflict with Selinunte, which was backed by Syracuse, which was friendly with Sparta.

The moderate Nicias opposed the expedition but was maneuvered into leading it when his warnings about its dangers were used as arguments for sending an even larger force.

The expedition became a perfect storm of bad leadership, political interference, and military miscalculation. Alcibiades was recalled on charges of religious sacrilege just as the campaign began. Nicias, never enthusiastic about the venture, proved overly cautious.

The Athenians found themselves besieging Syracuse, one of the most powerful cities in Sicily, with inadequate forces and no clear strategy for victory.

The disaster was complete. The entire expedition was destroyed, with most of the survivors sold into slavery. Athens lost not just ships and men but its aura of invincibility. It was as if a modern superpower had lost an entire carrier group along with its most experienced personnel.

Alcibiades after being recalled to Athens in 413 BC, defected to Sparta rather than returning and gave them crucial intelligence.

The final phase of the war saw a shift in strategy. Sparta established a permanent fort at Decelea in northern Attica, disrupting Athenian supply lines and encouraging revolts among its allies.

The destruction of the Athenian Sicilian expedition opened the door for Sparta to do something that would have been unthinkable earlier: ally with Persia, the great enemy of all Greeks.

The Persians, eager to weaken Athens, provided gold that allowed Sparta to build a fleet and challenge Athenian naval supremacy.

This final phase saw warfare of unprecedented intensity and violence. Both sides employed tactics that would have horrified earlier generations: mass executions of prisoners, the systematic destruction of neutral cities, and the use of “barbarian” Persian gold to settle Greek disputes.

The war had corrupted both sides, turning them into versions of themselves that their ancestors might not have recognized.

The end came at Aegospotami, in 405 BC, in what is modern-day Turkey, where the Spartan admiral Lysander destroyed the last Athenian fleet through a combination of tactical brilliance and Athenian overconfidence. With their fleet gone and their city under siege, the Athenians faced starvation and surrender.

The war ended with Sparta imposing harsh terms on Athens: the destruction of its long walls, the loss of its empire and navy, and the establishment of a pro-Spartan oligarchy known as the Thirty Tyrants.

Although Sparta emerged as the dominant power in Greece, its victory was short-lived.

The thirty-years of conflict between Athens and Sparta devastated the major Greek city-states, leaving them economically ruined, militarily exhausted, and politically fractured.

Athens, once the strongest naval power in the eastern Mediterranean, was defeated and stripped of its empire. Sparta, despite emerging victorious in 404 BC, lacked the administrative and financial infrastructure to maintain control over its new possessions and quickly alienated its former allies.

This led to renewed warfare among the Greek poleis, including conflicts like the Corinthian War and the Theban-Spartan war, all of which destabilized the region even further.

In the power vacuum that followed, Macedonia, long considered a peripheral and semi-barbaric kingdom to the north, was uniquely positioned to take advantage. They had been on the sidelines during most of the wars that were fought, avoiding most of the damage that the rest of Greece did.

Philip II, who ascended to the throne in 359 BC, had spent part of his youth as a hostage in Thebes, where he observed Greek military and political systems firsthand.

He utilized this knowledge to reform the Macedonian army, introducing the phalanx formation armed with long spears called sarissas, refining cavalry tactics, and centralizing authority.

As the Greek city-states remained mired in mutual suspicion and conflict, Philip expanded Macedonian territory and influence with relatively little unified resistance. His decisive victory over the Greek coalition at the Battle of Chaeronea in 338 BC marked the end of effective Greek independence.

Thus, the long-term disintegration of Greek unity and strength, caused by the Peloponnesian War, paved the way for Philip II’s rise, the subsequent Macedonian domination of Greece, and the emergence of Alexander the Great.

Perhaps most importantly, the Peloponnesian War brought about the end of the Golden Age of Classical Greece by destroying the political stability, economic prosperity, and cultural confidence that had defined the 5th century BC, particularly in Athens.

Much of what we think of when we think of Ancient Greece came from earlier in that century.

Athens was the intellectual, artistic, and democratic heart of the Greek world, producing achievements in philosophy, drama, architecture, and politics.

However, after the war with Sparta, it was never the same again.

Before I close, there is one other thing about the Peloponnesian War that deserves mention.

This war took place almost 2,500 years ago. Yet, we know far more about it than we do about any other war from this period in history. In many places, we might have an inscription on a tomb or other scant information we have to piece together.

For the Peloponnesian War, we know so much about it thanks to the aforementioned Thucydides.

His History of the Peloponnesian War, though unfinished, is one of the most important historical accounts to survive from antiquity and provides an in-depth narrative of the causes, events, strategies, speeches, and political dynamics of the war.

He was, in many senses, one of the first modern historians. Thucydides approached history with a critical and empirical mindset, rejecting myth and divine causality in favor of rational analysis, eyewitness accounts, and careful chronology.

He also included reconstructed speeches to explore the motives and reasoning of key figures, giving insight into the ideological and psychological dimensions of the war.

For example, earlier conflicts such as the Greco-Persian Wars are known largely through Herodotus, whose work mixes historical fact with anecdote and folklore. Other conflicts are known from authors who might have lived centuries after the fact.

The Peloponnesian War wasn’t the biggest war in history. It was smaller than the Greco-Persian Wars which preceded it. However, it was an important war insofar as it marked a transition in the history of Greek city-states and laid the foundation for the likes of Philip and Alexander, who came after.